Lake plastisphere as a new biotope in the Anthropocene: Potential pathogen colonization and distinct microbial...

Area of Science:

• Environmental microbiology
• Ecotoxicology
• Freshwater ecology

Background:

• Microplastic (MP) distribution in freshwater is uneven, leading to distinct microbial communities.
• The ecological role of the plastisphere, particularly in metabolic pathways and element cycling, is not well understood.

Purpose of the Study:

• To investigate the microbial composition and functional potential of the plastisphere on MPs in Taihu Lake.
• To compare the ecological characteristics of plastisphere communities with planktonic microbial communities.

Main Methods:

• Collection of MPs from 15 sampling sites in Taihu Lake.
• Metagenomic analysis to determine microbial taxonomic composition and functional profiles.
• Comparison of plastisphere communities with planktonic communities.

Main Results:

• MPs, primarily fibrous polyethylene terephthalate, were widespread and colonized by specific bacteria (Bacteroidia, Alpha-Proteobacteria, Bacilli), while Verrucomicrobiae were depleted.
• Plastisphere showed enrichment in plant pathogens and overrepresented functional genes for amino acid metabolism, secondary metabolite biosynthesis, and glycan metabolism.
• Significant alterations in elemental cycling were observed, including reduced nitrogen fixation/nitrification and enriched denitrification/nitrate reduction, alongside increased sulfate reduction and sulfur oxidation.
• Plastisphere microbial communities were primarily shaped by stochastic processes, contrasting with deterministic processes dominating planktonic communities.

Conclusions:

• The plastisphere represents a unique anthropogenic ecosystem within freshwater environments.
• MPs significantly influence microbial community structure, function, and elemental cycling in aquatic ecosystems.
• Distinct ecological mechanisms govern plastisphere and planktonic microbial communities.